Rockford Fosgate 250 - Manual (Page 27)

– 22 –
Symptom Diagnosis Remedy
TROUBLE- S
H
O
O
T
I
N
G
Voltage spike from remote
turn-on lead is entering
through REM input terminal.
Noise is radiating into RCA
signal cable.
Bad component in the signal
chain.
Noise is radiating into speaker
cables.
Multiple grounds in the
audio system.
Ground loop between source
unit and antenna.
TOPAZ input circuitry (in Rock-
ford amps) or floating input
circuitry (in non-Rockford
amps) does not have refer-
ence to “chassis ground.” This
noise, if any, occurs at the
auxiliary amplifier whose in-
puts are fed from the pass-
thru output of the first amp.
Engine Noise
Use a different 12 volt source for
REM lead of amplifier (i.e., battery
direct). If noise is eliminated, use a
relay to isolate amplifier from noisy
turn-on output.
Check connections, run the RCA
cables on a different route away
from sources of high current.
Check connections, bypass addi-
tional components (crossovers and
equalizers) between the source unit
and the amplifier. Connect one
component at a time to determine
the culprit. Repair or replace com-
ponents as necessary.
Disconnect existing speakers and
connect a test speaker to the output
terminals of the amplifier. If noise is
gone, reroute the speaker cables
away from sources of high voltage.
Check ground connections and
connect amplifiers, signal proces-
sors, and other components to a
central location or try a different
grounding point on the chassis.
Check connections, disconnect
antenna from source unit. If noise is
gone, install an antenna ground
loop isolator.
Supply reference ground to the
TOPAZ input circuit (or floating in-
put circuit in non-Rockford amps).
Connect shield of RCA input from
auxiliary amp to chassis ground of
radio. An alternative method is to
connect the RCA shield to the
amplifier's power ground terminal.
• If noise persists, see your Authorized Rockford Fosgate Dealer.
Engine Noise when
using high level
inputs
Amplifier Noise
(Turn-on Pop)